(a) Field of the Invention
This invention relates to a process for preparing cardiotonically active 1,2-dihydro-6-methyl-2-oxo-5-(pyridinyl)nicotinonitriles.
(b) Description of the Prior Art
Lesher, Opalka and Page U.S. Pat. No. 4,276,293, issued June 30, 1981 and based on application Ser. No. 135,211, filed Mar. 28, 1980, discloses the process for preparing a 1,2-dihydro-6-(lower-alkyl)-2-oxo-5-(pyridinyl)nicotinonitrile by first reacting a pyridinylmethyl lower-alkyl ketone with dimethylformamide di-(lower-alkyl) acetal to produce a 1-(pyridinyl)-2-(dimethylamino)ethenyl lower-alkyl ketone and then reacting said ketone with alpha-cyanoacetamide.
Opalka and Lesher U.S. Pat. No. 4,223,149, issued September 16, 1980, discloses and claims the process for preparing a 1,2-dihydro-2-oxo-5-(pyridinyl)nicotinonitrile by reacting alpha-(pyridinyl)-beta-[di-(lower-alkyl)amino]acrolein with malononitrile in a lower-alkanol.